The film opens with a group of men about to watch a movie. Two officers, one a moderator, introduce the movie, thus sandwiching it between this introductory scene and a closing commentary. The brief opening remarks admit that the movie about to be shown is simplistic.
The movie is about two novice spies, Al and Charles. The country that each spy is to infiltrate is not identified by name as a real country. Both spies are going to "Enemy Area", even though they might not be going to the same country. One is heading for Enemy City while the other is aiming for a seaport called El Porto.
In one scene, Al is on a train. The conductor, like all officials that both Al and Charles run across, has an armband with a checkerboard on it. (If you contemplate it, you soon realize that the "checkerboard" is really a swastika with all of its arms turned into closed boxes.) The conductor asks Al for his papers and asks a lot of other questions.
"Where are you going?"
"Enemy City", replies Al.
If he said that in real life, he would be hanging by his curlies by nightfall, but, of course, the generic place names are just the conceit of the movie. Geography is unimportant. Procedure, or what spies call "tradecraft", is everything here. (Although in the ending scene where the moderator discusses the film, he points out that in the Far East, a lot of the rules taught in the movie would have to be different.)
The plot is reminiscent of the story of the grasshopper and the ant. The grasshopper agent is overconfident and arrogant. He reads magazines instead of studying. The ant does his homework and remembers his lessons in the field. They learn some of their lessons with their handlers in the comfort of their home country, but when they get to "Enemy Area", the narrator and other characters they meet tell us what lessons they have to learn or are being reinforced on the job. The lessons can be common sense but aren't always.
Al arrives in Enemy City and must find a place to stay. First he considers a big hotel, but Al reflects that the secret police are likely focusing on the big hotels, which will be crawling with informers; the whole staff will be regularly questioned by police. Besides, his cover is that he is a machinist. What would he be doing in a fancy hotel? Rule one is to be inconspicuous.
He goes on to a private home that lets rooms. Maybe later when he gets established. For now, living with a family might be too constraining. They will ask where he is going and so on. So he moves on to a rooming-house where he might have a little more anonymity, but he overhears the landlady gossiping disapprovingly about one of her tenants. She is nosy and will watch him like a hawk.
So he goes on until he finds a small hotel. There are too many of these second rate hotels for the police to check up on all of them. It is within the budget of a machinist, and it will give him some anonymity. He takes it. There are hundreds or even thousands of little decisions like this that the spy has to make.
After the movie ends and we return to the outer story of the film, the moderator points out that the real usefulness of this movie is for a class to go over in more detail all of the points that are made superficially.
The moderator also points out some things that were not given attention but perhaps should have been. For example, didn't the grasshopper's handler make a mistake by sending him into the field knowing that the man was overconfident and had a cavalier and impetuous attitude?
Another detail: When Al is pacing nervously around his hotel room and chain smoking, he stubs out a half-smoked cigarette in an ashtray. This is probably a country where tobacco is being rationed. Might the hotel maid and others be suspicious of someone who acts as if, where they come from, cigarettes are easy to come by?
This is a kind of industrial/educational film that is explicitly meant to be studied and discussed for the insights that can be gleaned about undercover work, a very peculiar endeavor that requires a combination of training, native intelligence and attention to detail combined with an ability to think on one's feet.
The sound of this movie is poor. Captions are helpful or even essential. Without any credits you might not know that John Ford directed it or that he plays a supporting role. The two lead actors look familiar but are not named.